The previous link also includes some comments from the Peter Diamandis talk at the ISDC. In addition to the potential prizes listed there, Diamandis also described a few other ideas (all presumably pending funding and additional development). The one I'll mention here is "Lunar Lander Challenge Level 3". I don't have my notes handy (I haven't unpacked from the conference yet), but as I recall the idea was to have a Lunar Lander Challenge that is similar to the one we know, but with no refueling allowed. Staging would be allowed.

Today, we announce that after close consultation with our teams over the last few months, that there will not be a launch attempt by our March 31st, 2018 deadline, and the grand prize of the $30 million Google Lunar XPRIZE will go unclaimed.

While we are disappointed at the result, XPRIZE is exploring a number of ways to proceed from here, and we are proud of the impact that the Google Lunar XPRIZE has achieved to date. Stay tuned for exciting updates in the near future.